Metadata "retry"

Setting the retry metadata provides control over how many times an action is re-scheduled on error before it is finally treated as a failure.

• Type: number|boolean
• Default: 1

It is commonly used conjointly with the attempt metadata which provides an indicator over how many times an action was rescheduled.

Usage

The default value is 1 which means that actions are not rescheduled on error.

If provided as a number, the value must be superior or equal to 1. For example, the value 3 means the action will be executed a maximum of 3 times. If the third time the action fails, then it will be treated by the Nikita session as a failed action.

const assert = require('assert');
nikita
// Call an action
.call({
  $retry: 3}, ({metadata}) => {
  // First 2 attempts failed with an assertion error,
  // but the 3rd one succeeded
  assert.equal(metadata.attempt, 2)
})

Boolean value

Setting the value as true causes unlimited number of retries:

const assert = require('assert');
nikita
// Call an action
.call({
  $retry: true}, function ({metadata}) {
  // First 9 attempts failed with an assertion error,
  // but 10th attempt succeeded
  assert.equal(metadata.attempt, 9)
})

The value false is the same as 1.

With the relax metadata

When used with the relax metadata, every attempt will be rescheduled. Said differently, marking an action as relax will not prevent the action to be re-executed on error.

const assert = require('assert');
(async () => {
  var {$status} = await nikita
  // Call an action
  .call({
    $retry: 2,    $relax: true  }, () => {
    // Will fail 2 times
    throw Error('Oups')
  })
  // Will be executed because the action was not fatal
  assert.equal($status, false)
})()